PROJECT SUMMARY/ABSTRACT Pancreatic adenocarcinoma is an aggressive malignancy that often presents with advanced disease. Even in those patients deemed to have resectable disease by conventional imaging (CT scan or MRI), many are found to have more advanced cancer at the time of surgical exploration. In these patients, surgery is not beneficial. Thus, patients are exposed to the morbidity of unnecessary surgery and the resultant delays in the most appropriate therapy; namely, systemic chemotherapy. Second, determining the response to neoadjuvant treatment in patients with borderline resectable or locally advanced pancreatic cancer is inadequate, as differentiating treatment response/inflammation from tumor progression is difficult with conventional imaging. Often, these patients are taken to surgery, found to have unresectable disease and, in a similar fashion to the aforementioned situation, are exposed to all of the risks of surgery with no possible benefit. In sum, improved methods of pancreatic cancer staging are needed to improve patient selection for treatment (surgery, chemotherapy, and/or radiation). This will reduce the morbidity and treatment delays associated with futile surgery and will also reduce costs and better allocate scarce and expensive treatment-related resources (i.e. operating room time). The novel combined imaging modality of positron emission tomography and magnetic resonance imaging (PET-MRI) has the potential to address these current shortcomings. PET-MRI combines the precise anatomic detail of MRI with the functional imaging of PET. This has the potential to better delineate the extent of a tumor and differentiate viable cancer from treated/necrotic tumor. We hypothesize that PET-MRI will have improved ability to both detect occult metastatic disease in the pre-treatment evaluation of patients with pancreatic cancer and determine response to neoadjuvant treatment when compared to conventional imaging (CT and MRI). In this regard, the aims of this study are to (1) determine if there is a benefit of PET-MRI in the pre-operative staging of patients with pancreatic adenocarcinoma and (2) to utilize PET-MRI in determining response to treatment in patients with pancreatic cancer enrolled on a neoadjuvant clinical trial at our institution. If successful and validated in large studies, PET-MRI has the potential to better select patients for appropriate therapy, thus sparing patients unnecessary morbidity and, ultimately, improve long-term outcomes in patients with pancreatic cancer.